Automatic techniques in civil air line communication systems

The applications of automatic data transfer techniques to the airborne components of the aeromobile service are concerned with ¿machineable¿ methods of modulation and coding, and with input/output devices of a much higher degree of sophistication than such familiar transducers as microphones and telephones. The internal characteristics of the traffic which are important in the selection of coding methods can be seen from a system of classification. Aeromobile traffic can be divided into three categories, whose internal characteristics are so different that each demands its own particular coding techhique. The optimum solution appears to demand the use of three sub-systems, each properly related to the others so that the end result is a single system. One of these sub-systems already exists, namely the radio telephone; the others so far exist only in elementary or experimental forms. The methods of integration, both procedural and functional, which are required to ensure that the three sub-systems are assembled into a single coherent system are discussed.